Gear and spatial measures to reduce benthic impacts of beam trawl fisheries in the North Sea

Depestele, J. (Speaker), Lenoir, H. (Speaker), Jan Geert Hiddink (Speaker), Polet, H. (Speaker), Vanderperren, E. (Speaker), Van Hoey, G. (Speaker)

Activity: Talk or presentationLecture and oral contribution

Description

Flatfish-directed beam trawls penetrate the seabed and alter the functioning of the benthic ecosystem of its target species. A framework was developed to assess these types of seabed impacts for bottom-contacting mobile gears in the North Sea. The framework combines fishing effort (swept area ratio) with the gear penetration depth to assess the instantaneous mortality of benthic species living in the seabed. The recovery rate of the depleted benthic community is estimated using a population dynamic model to assess the relative change in benthic state. In this study we apply this framework to the Belgian beam trawl fisheries to estimate their seabed impact, while accounting for the fishing pressure of other European fleets. The objective of the study is twofold. First, we will assess the evolution of the annual seabed impact of the Belgian beam trawl fleet. Second, we will assess how this fleet may reduce its impact through gear modifications or changes in spatial effort distribution. The reduced impact of gear modifications, such as the Sumwing, is due to a reduction in seabed penetration and subsequent benthic mortality. The reduced impact of spatial effort distribution is related to the differences in recovery potential and equilibrium state of benthic communities. Our case study will test a quantitative means to assess seabed impacts of a specific, national fleet and allows to trade-off spatial and gear-related measures to reduce that impact.
Period5-Jul-20219-Jul-2021
Event titleFSBI Symposium (Fisheries Society of the British Isles): Fish, Fisheries and Ecosystems in the Anthropocene
Event typeConference
LocationLeuven, Belgium
Degree of RecognitionInternational